An oil-based drill cuttings treatment device and method

Abstract

The present invention discloses an oil-based drill cuttings treatment device and method. The oil-based drill cuttings treatment device includes: a pyrolysis unit for thermally desorbing oil-based drill cuttings; and a condensation unit for condensing the oil and gas generated by the thermal desorption. The concentrated brine obtained after the reverse drainage liquid undergoes reverse osmosis treatment is used as the cold source of the condensation unit. The oil-based drill cuttings treatment method is characterized in that the method includes: Step 1): thermally desorbing the oil-based drill cuttings to obtain oil and gas; Step 2): using the concentrated brine obtained after the reverse drainage liquid undergoes reverse osmosis treatment as the cold source to condense the oil and gas to obtain oil. The present invention uses the concentrated brine obtained after treating the reverse drainage liquid as the cold source of the condensation unit, so that while condensing the oil and gas generated by the thermal desorption, the concentrated brine is heated, thereby forming crystalline salts, reducing the cost of subsequent treatment of the concentrated brine and reducing energy consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil drilling, and particularly relates to an oil-based drill cuttings treatment device and method. Background Art

[0002] In the oil industry, drilling is an essential process for oil production. Among them, oil-based drilling fluid is a stable colloidal system with oil (diesel or white oil) as the continuous phase, water as the dispersed phase, and containing appropriate emulsifiers, wetting agents, oilophilic colloids, weighting agents, etc. It has the characteristics of safety, strong inhibition, good lubricity, and high drilling speed. Therefore, it is widely used in the horizontal section drilling of shale (oil) gas wells, special complex wells, etc. A large amount of oil-containing drill cuttings, namely oil-based drill cuttings, generated during the drilling process contain a large amount of mineral oil and the above additives, and belong to hazardous solid waste. If not properly treated, on the one hand, it will cause serious harm to the surrounding environment, and on the other hand, it will waste a large amount of mineral oil resources. The treatment of oil-based drill cuttings is usually carried out by thermal desorption.

[0003] At the same time, during the oil drilling process, a large amount of reverse drainage fluid is generated. Among them, the salt content of the reverse drainage fluid is relatively high. After RO reverse osmosis treatment, the salt content in the obtained concentrated brine can reach about 6-10%. If the concentrated brine is dried to obtain crystalline salt, in the prior art, the concentrated brine obtained by reverse osmosis is directly sent to a falling-film evaporator for further concentration, and then heat energy is used for crystallization. This treatment process requires a very high energy consumption. Summary of the Invention

[0004] Aiming at the deficiencies and defects existing in the prior art, the purpose of the present invention is to provide an oil-based drill cuttings treatment device and method.

[0005] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0006] An oil-based drill cuttings treatment device, comprising:

[0007] A pyrolysis unit for thermally desorbing oil-based drill cuttings; and a condensation unit for condensing the oil and gas generated by the thermal desorption.

[0008] The concentrated brine obtained after the reverse drainage fluid is treated by reverse osmosis is used as the cold source of the condensation unit.

[0009] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the salt content of the concentrated brine is 6-10 wt.%.

[0010] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the oil-based drill cuttings treatment device further includes a combustion unit, and the hot gas generated by the combustion unit can be used as the heat source for the thermal desorption in the pyrolysis unit.

[0011] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the combustion unit is a combustion furnace.

[0012] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the condensation unit includes a condenser. The oil and gas inlet of the condenser is connected to the oil and gas outlet of the pyrolysis unit, and the concentrated brine is used as the cold source of the condenser to condense the oil and gas entering the condenser from the pyrolysis unit.

[0013] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the condensation unit further includes a first air exchanger. The oil and gas inlet of the first air exchanger is connected to the oil and gas outlet of the pyrolysis unit, and the oil and gas outlet of the first air exchanger is connected to the oil and gas inlet of the condenser. The cold medium of the first air exchanger is air, which is used to condense the oil and gas entering the first air exchanger. The oil and gas first enter the first air exchanger for heat exchange and then enter the condenser for condensation.

[0014] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the air outlet of the first air exchanger is connected to the combustion unit, and the air flowing out of the first air exchanger enters the combustion unit to participate in the combustion reaction.

[0015] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the oil-based drill cuttings treatment device further includes a combustion tail gas treatment unit. The combustion tail gas is the hot gas that has undergone heat exchange with the pyrolysis unit, and the temperature of the combustion tail gas is 300 - 500 °C.

[0016] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the combustion tail gas treatment unit includes a second air exchanger. The combustion tail gas inlet of the second air exchanger is connected to the combustion tail gas outlet of the pyrolysis unit. The combustion tail gas enters the second air exchanger to exchange heat with air.

[0017] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the air outlet of the second air exchanger is connected to the combustion unit, and the air flowing out of the second air exchanger enters the combustion unit to participate in the combustion reaction.

[0018] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the air outlet of the second air exchanger is connected to the air inlet of the first air exchanger.

[0019] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the combustion exhaust gas treatment unit further includes a heat exchanger, and the combustion exhaust gas inlet of the heat exchanger is connected to the combustion exhaust gas outlet of the second air exchanger; the combustion exhaust gas that has undergone heat exchange in the second air exchanger enters the heat exchanger for cooling, and the cold source of the heat exchanger is the concentrated brine.

[0020] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the oil-based drill cuttings treatment device further includes a drying unit, and the concentrated brine outlet of the condenser is connected to the inlet of the drying unit; the drying unit is used to dry the concentrated brine flowing out of the condenser, thereby forming crystalline salt.

[0021] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the concentrated brine outlet of the heat exchanger is connected to the inlet of the drying unit; the drying unit is used to dry the concentrated brine flowing out of the cooler, thereby forming crystalline salt.

[0022] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the concentrated brine outlet of the heat exchanger is connected to the concentrated brine inlet of the condenser, and the concentrated brine treated by the heat exchanger can be used as the cold source of the condenser.

[0023] In the above oil-based drill cuttings treatment device, as a preferred embodiment, the drying unit is a multi-effect drying tower.

[0024] An oil-based drill cuttings treatment method, the method comprising:

[0025] Step 1): Thermally desorb the oil-based drill cuttings to obtain oil and gas;

[0026] Step 2): Use the concentrated brine obtained after reverse osmosis treatment of the reverse drainage liquid as a cold source to condense the oil and gas to obtain oil.

[0027] In the above oil-based drill cuttings treatment method, as a preferred embodiment, the oil and gas is first air-cooled and then condensed.

[0028] In the above oil-based drill cuttings treatment method, as a preferred embodiment, the air used to cool the oil and gas is heated by the combustion exhaust gas discharged from the equipment that has completed the thermal desorption.

[0029] In the above oil-based drill cuttings treatment method, as a preferred embodiment, the air used to cool the oil and gas enters the combustion unit for combustion; the heat source for the thermal desorption is provided by the combustion unit.

[0030] In the above oil-based drill cuttings treatment method, as a preferred embodiment, the combustion tail gas is heat-exchanged with the concentrated brine obtained after the reverse drainage liquid undergoes reverse osmosis treatment to heat the concentrated brine.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) Compared with the traditional method of directly spraying hot oil gas with water, then performing oil-water separation, cooling the water and recycling it, and regularly treating wastewater, the present invention innovatively uses a condensation unit to condense the oil gas generated by thermal desorption, introduces the concentrated brine generated by treating the reverse drainage liquid into the thermal desorption heat energy utilization system, thereby simplifying the process, reducing costs, obtaining high-quality oil, and the oil can be directly used. The treatment device and method of the present invention do not generate sewage, have low energy consumption and little pollution.

[0033] (2) The present invention uses the concentrated brine obtained after treating the reverse drainage liquid as the cold source of the condensation unit. In this way, while condensing the oil gas generated by thermal desorption, the concentrated brine is heated, reducing the cost of subsequent treatment of the concentrated brine and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a schematic structural diagram of the oil-based drill cuttings treatment device of the present invention;

[0035] Among them, 1 is a combustion furnace, 2 is a pyrolysis furnace, 3 is a condenser, 4 is a first air exchanger, 5 is a second air exchanger, 6 is a heat exchanger, and 7 is a multi-effect drying tower. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] In order to highlight the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with embodiments. The examples are expressed by way of explanation of the present invention rather than limiting the present invention. The technical solution of the present invention is not limited to the following specific embodiments listed, but also includes any combination between the specific embodiments.

[0037] Example 1:

[0038] The present invention provides an oil-based drill cuttings treatment device, which includes:

[0039] A combustion furnace 1, for example, the energy of natural gas is burned in the combustion furnace 1 to generate heat. The temperature of the hot gas (which is the combustion tail gas after passing through the pyrolysis furnace 2) generated by the combustion furnace 1 is 300 - 500 °C;

[0040] A pyrolysis furnace 2, the pyrolysis furnace 2 is connected to the combustion furnace 1, uses the hot gas generated in the combustion furnace 1 as the heat source, and the oil-based drill cuttings generated during the drilling process are thermally desorbed in the pyrolysis furnace 2 (the temperature of the thermal desorption furnace is 330 - 400 °C) to generate hot oil gas, and its temperature can reach about 330 °C;

[0041] Condenser 3. The hot oil gas generated by the pyrolysis furnace 2 enters the condenser 3. The cold source of the condenser 3 is the concentrated brine obtained after the reverse drainage liquid is treated by reverse osmosis. After being condensed by the concentrated brine, the oil content contained in the hot oil gas is condensed into oil, enabling the simple recovery of the oil content; preferably, a first air exchanger 4 is also provided between the pyrolysis furnace 2 and the condenser 3. The oil gas inlet of the first air exchanger 4 is connected to the oil gas outlet of the pyrolysis furnace 2, and the oil gas outlet of the first air exchanger 4 is connected to the oil gas inlet of the condenser 3. The hot oil gas first enters the first air exchanger 4. Through the action of the cold medium air in the first air exchanger 4, the temperature of the hot oil gas is reduced to 280 - 300 °C. At this time, a part of the oil content will be condensed into oil. Then, the cooled oil gas enters the condenser 3 for further condensation, thereby recovering the oil again. The oil gas condensed by the condenser 3 enters the combustion furnace 1 to participate in combustion; preferably, the first air exchanger 4 is connected to the combustion furnace 1, and the air that has undergone heat exchange with the hot oil gas in the first air exchanger 4 enters the combustion furnace 1 to participate in combustion. At the same time, after the concentrated brine undergoes heat exchange with the first air exchanger 4 and the condenser 3, the temperature of the concentrated brine rises. The temperature of the concentrated brine coming out of the condenser 3 rises from the initial temperature of 23 - 28 °C to 55 - 65 °C.

[0042] This oil-based drill cuttings treatment device further includes a combustion tail gas treatment unit. The combustion tail gas treatment unit includes a second air exchanger 5 and a heat exchanger 6. The combustion tail gas inlet of the second air exchanger 5 is connected to the combustion tail gas outlet of the pyrolysis furnace 2, and the combustion tail gas outlet of the second air exchanger 5 is connected to the combustion tail gas inlet of the heat exchanger 6. Specifically, after the combustion tail gas generated by the combustion furnace 1 undergoes heat exchange in the pyrolysis furnace 2, it is, for example, about 300 °C. Then, the combustion tail gas enters the second air exchanger 5 and is cooled under the action of the cold medium air, and then enters the heat exchanger 6. The cold source of the heat exchanger 6 is preferably the concentrated brine obtained after the reverse drainage liquid is treated by reverse osmosis. After passing through the heat exchanger 6, through heat exchange, the temperature of the concentrated brine has increased; the air outlet of the second air exchanger 5 is connected to the air inlet of the combustion furnace 1, and the air that has undergone heat exchange with the combustion tail gas in the second air exchanger 5 enters the combustion furnace 1 to participate in combustion;

[0043] Preferably, the first air exchanger 4 and the second air exchanger 5 are connected. The air first undergoes heat exchange in the second air exchanger 5, and the temperature of the air after heat exchange is about 100 °C; then it enters the first air exchanger 4 to undergo heat exchange with the hot oil gas, and the temperature of the air after heat exchange is about 160 °C; then the air enters the combustion furnace 1 to participate in combustion.

[0044] The oil-based drill cuttings treatment device further includes a drying unit for drying the concentrated brine after being treated by the condenser 3 and the heat exchanger 6. The drying unit is preferably a multi-effect drying tower 7. After passing through the multi-effect drying tower 7, crystalline salts are formed. The concentrated brine after being treated by the condenser 3 and the concentrated brine after being treated by the heat exchanger 6 are mixed (as shown in Figure 1), and then enter the multi-effect drying tower 7 for drying; preferably, the concentrated brine after being treated by the heat exchanger 6 first enters the condenser 3 and then enters the multi-effect drying tower 7 for crystallization into salts. The concentrated brine entering the multi-effect drying tower 7 only needs to meet the requirements of the multi-effect drying tower 7. The concentrations of the concentrated brine after being treated by the condenser 3 and the concentrated brine after being treated by the heat exchanger 6 can be achieved by adjusting the proportion of the cold source and the heat source and the contact area between the cold source and the heat source entering the condenser 3 and the heat exchanger 6..

[0045] The above embodiments have described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the principle of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. An oil-based drill cuttings treatment device, characterized in that, Comprising: A pyrolysis unit for thermally desorbing oil-based drill cuttings; And a condensation unit for condensing the oil and gas generated by the thermal desorption; The concentrated brine obtained after the reverse osmosis treatment of the backflow liquid is used as the cold source of the condensation unit, The condensation unit includes a condenser. The oil and gas inlet of the condenser is connected to the oil and gas outlet of the pyrolysis unit. The concentrated brine is used as the cold source of the condenser to condense the oil and gas entering the condenser from the pyrolysis unit; The condensation unit further includes a first air exchanger. The oil and gas inlet of the first air exchanger is connected to the oil and gas outlet of the pyrolysis unit. The oil and gas outlet of the first air exchanger is connected to the oil and gas inlet of the condenser. The cold medium of the first air exchanger is air, which is used to condense the oil and gas entering the first air exchanger. The oil and gas first enter the first air exchanger for heat exchange and then enter the condenser for condensation; The air outlet of the first air exchanger is connected to the combustion unit, and the air flowing out of the first air exchanger enters the combustion unit to participate in the combustion reaction; The oil-based drill cuttings treatment device further includes a combustion exhaust gas treatment unit. The combustion exhaust gas is the hot gas that has undergone heat exchange with the pyrolysis unit, and the temperature of the combustion exhaust gas is 300-500°C, The combustion exhaust gas treatment unit includes a second air exchanger. The combustion exhaust gas inlet of the second air exchanger is connected to the combustion exhaust gas outlet of the pyrolysis unit. The combustion exhaust gas enters the second air exchanger for heat exchange with air; The air outlet of the second air exchanger is connected to the combustion unit, and the air flowing out of the second air exchanger enters the combustion unit to participate in the combustion reaction; The air outlet of the second air exchanger is connected to the air inlet of the first air exchanger; The combustion exhaust gas treatment unit further includes a heat exchanger. The combustion exhaust gas inlet of the heat exchanger is connected to the combustion exhaust gas outlet of the second air exchanger. The combustion exhaust gas that has undergone heat exchange in the second air exchanger enters the heat exchanger for cooling, and the cold source of the heat exchanger is the concentrated brine.

2. The oil-based drill cuttings treatment device according to claim 1, wherein The salt content of the concentrated brine is 6-10 wt%.

3. The oil-based drill cuttings treatment device according to claim 1, characterized in that, The oil-based drill cuttings treatment device further includes a combustion unit. The hot gas generated by the combustion unit is used as the heat source for the thermal desorption in the pyrolysis unit. The combustion unit is a combustion furnace.

4. The oil-based drill cuttings treatment device according to any one of claims 1 to 3, characterized in that The oil-based drill cuttings treatment device further includes a drying unit. The concentrated brine outlet of the condenser is connected to the inlet of the drying unit. The drying unit is used to dry the concentrated brine flowing out of the condenser to form crystalline salt. The drying unit is a multi-effect drying tower.

5. The oil-based drill cuttings treatment device according to claim 4, wherein, The concentrated brine outlet of the heat exchanger is connected to the inlet of the drying unit; The concentrated brine outlet of the heat exchanger is connected to the concentrated brine inlet of the condenser. The concentrated brine treated by the heat exchanger can be used as the cold source of the condenser.

6. A method for treating oil-based drill cuttings using the base drill cuttings treatment device according to any one of claims 1 to 5, characterized in that, The method includes: Step 1): Thermally desorb the oil-based drill cuttings to obtain oil and gas; Step 2): Use the concentrated brine obtained after the reverse drainage is treated by reverse osmosis as a cold source to condense the oil gas to obtain oil.

7. The oil-based drill cuttings treatment method according to claim 6, wherein First, air-cool the oil gas, and then perform the condensation; The air used to cool the oil gas is heated by the combustion tail gas discharged from the equipment that has completed the thermal desorption; The air used to cool the oil gas enters the combustion unit for combustion; the heat source for the thermal desorption is provided by the combustion unit; The combustion tail gas exchanges heat with the concentrated brine obtained after the reverse drainage is treated by reverse osmosis to heat the concentrated brine.

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